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  • Author or Editor: T. J. Sheehan x
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Abstract

Platyceriums (staghorn ferns) are propagated commercially by 2 methods: asexually by offshoots and sexually by spores. Many of the Platycerium species (e.g. P. stemaria, P. bifuractum) reproduce asexually by offshoots from roots or rhizome quite readily and are easily increased by removal of these offshoots. However, some of the larger and more sought after species (e.g., P. wandae, P. grande, P. superbum) do not produce offshoots or do so sparingly. These species must be propagated sexually through the use of spores. This technique is generally slow and may require 2-4 years to obtain a marketable plant. Rapid propagation of these slow growing staghorn ferns through tissue culture could prove to be economically beneficial to the foliage industry.

Open Access
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Abstract

Lisianthus russellianus Hook., syn. Eustoma grandiflorum, belongs to the Gentianacea and is native from the plains of Nebraska to Louisiana and Mexico. It is a tender annual, grows 45 cm high, and produces 5 lobed, purple, dark-eyed flowers in summer and fall. The flowers have been described as large as 10 cm across under favorable conditions and to number as many as 10 or more on a plant. Flowers have lasted up to 2 weeks.

Open Access

Abstract

Phalaenopsis species often exhibit light green spots and/or pitting of the upper leaf surface during winter and spring. Results of this study indicate spotting and pitting can be induced by exposure to temperatures of 2°, 4°, and 7°C for 8 hours or less. The spots and/or pitted areas were always found between large vascular bundles. Light green or yellow spots on the leaves were caused by hypertrophied mesophyll cells between the main vascular bundles. Anatomical observations revealed the pitting was due to collapsed mesophyll cells. Severity of response depended on physiological age of the leaf and duration of exposure to the chilling temperature.

Open Access

Abstract

Cultivars of Kalanchoe blossfeldiana Poelln. varied in number of long nights required for complete flower initiation and development. ‘Montezuma’ and ‘Texas Sunset’ requried 14 long nights, while ‘Pixie’, ‘Nugget’, ‘Cactus Candy’, ‘Goddess’, ‘Tobasco’, ‘Osage Orange’, ‘Toltec’, ‘Adobe Rose’ and ‘Rotkappchen’ required 15 to 28 nights. Height of apical meristems increased in ‘Montezuma’ after 7 long nights, but changes were not evident in ‘Pixie’ until 9 long nights. Scanning electron microscopic analysis showed first evidence of sepal primordia in ‘Pixie’ after 28 long nights—6 nights later than ‘Montezuma’. Differences in the number of long nights required for flower induction were related to delayed floral initiation rather than organogenisis or maturation.

Open Access

Abstract

A technique using salinized agar as a germination medium in sealed, plastic petri dishes is described. Agar concentrations of 0.5%, 1%, 2%, and 3% solidified with up to 35,000 mg·liter−1 of total salts derived from a formula for full-strength seawater. Water loss from petri dishes sealed with a plastic film after 28 days averaged 1.7% and was negligible. Saline-agar media held more moisture initially and lost less water than standard, double germination blotters after 7 days. Germination of perennial ryegrass (Lolium perenne L. ‘Derby’) on unsalinized agar was not different from germination on unsalinized blotters. Total germination of ‘Derby’ perennial ryegrass averaged 94% and was unaffected by salt concentrations up to 5000 mg·liter−1 but germination rate (days to 50% germination) was progressively delayed from 3.98 ± 0.09 days for the controls having no salinity to 5.15 ± 0.33 days at 5000 mg∙liter−1 of salinity.

Open Access

Abstract

Gibberellic acid (GA)-treated ‘Redwing’ azaleas (Rhododendron spp.) flowered in half the time required for cold-treated plants. Visual plant quality and flower uniformity were equal in both treatments. Ethylene evolution of buds was monitored in plants receiving cold treatment, receiving GA application, or remaining in the greenhouse without a dormancy-breaking treatment. Ethylene was not detectable in untreated plants or in cold-treated plants during cold treatment. Ethylene in buds was detected on the 4th day after removal from the cooler and was found to correspond to ethylene generation in GA-treated plants.

Open Access

Abstract

Florida's ornamental horticulture industry, like the vegetable and fruit industries, has been shaped by Florida's long growing season, mild winters, and high light levels.

Open Access

Abstract

Aphelandra squarrosa Nees. plants grown under 250 μmol s−lm−2 photosynthetically active radiation (PAR) were transferred to 265, 737, and 1070 μmol s−1m−2. Stomatal density and number of palisade layers of newly expanded leaves decreased linearly after 2 months, while number of countable chloroplasts per palisade cell increased linearly as light intensity decreased. Number of countable chloroplasts per palisade cell decreased and palisade layers increased in mature leaves transferred to higher PAR levels. Stomatal density and guard cell length in mature leaves did not change. There were nonlinear responses to PAR levels in number of marginal collenchyma cells, leaf thickness, and palisade cell length of immature leaves. Chloroplasts in mature and immature leaves were less discrete and more tightly appressed to anticlinal palisade cell walls as PAR levels increased.

Open Access

Abstract

Silvernerve plant (Fittonia verschaffeltii ssp. argyroneura Coem.), a chill-sensitive foliage plant, was subjected to 2°, 5°, and 8° ± 1°C for 0, 2, 4, or 8 hours. Chilling temperatues caused leaf wilt, inflorescence collapse and brown necrotic spots on the foliage. Severity of chill damage increased with temperature reduction and duration.

Open Access